The present invention relates to a gas spring of the type including a cylinder filled with gas and in which a piston, provided with a piston rod, is guided.
Gas springs of the foregoing type are utilized, for example in motor vehicles and are usually arranged on engine flaps, trunks, covers or engine cowlings wherein the gas springs facilitate weight compensation and also exert onto the structural components a damping action during the shutting of those components.
The progression of a spring force of the gas spring should be adjusted by a multiple loading of the pressure chambers of the spring with a more or less compressed gas to respective operational ratios. For example, as disclosed, in DE-AS1,208,951, col. 1, lines 38-40, a filling pressure of the pressure chamber of the spring is more than 70 atu.
The disadvantage of such gas springs resides in that, for example during a traffic accident the structural components of the gas springs can slip out from the car elements and seriously injure people involved in the accident.
It has been suggested to avoid such a danger to provide the gas springs with safety limits which would ensure that in case of a forceful action or overloads the gas cushions remaining under high pressure could harmlessly escape from the springs.
The safety arrangements in gas springs suggested up to now offer some warrenty for avoiding great danger in cases of failure or accidents. On the other hand these safety arrangements included groove-shaped notches in the outer regions of the piston rods and pressure cylinders which could not be precisely defined. It is known that such notches can cause fatigue breaks in metallic components and the damage can not be practically appraised. The arrangement of breaking points or notches has required a great deal of precision during the manufacture, and finally a force causing breaks under corresponding various operational conditions is not calculable. Furthermore with the provision of breaking points on the elements of the gas springs a certain unsafety still remains so that the problems which could occur in case of a traffic accident have not yet been solved with the known arrangements.